Collisions between of a symmetric top with a linear molecule in a ¹Σ state

BASISTYPE = 9

System subroutine: systpln

Basis subroutine: hiba09_stpln.F90

Ref. C. Rist, M. H. Alexander, and P. Valiron, J. Chem. Phys. 98, 4662 (1993).

The definition of the integer system dependent parameters is as follows:

• NTERM: (the number of potential surfaces involved: this should be 2 in this case). This parameter can not be changed
• NUMPOT: an index representing the particular potential used. This variable is passed to the POT subroutine
• IPOTSY: cylindrical symmetry of potential. If the flag IHOMO = .True., only terms with mu₁ equal to an integer multiple of IPOTSY can be included in the potential. Example: for NH3, IPOTSY = 3
• IOP: ortho/para label for rotational states of diatomic. If IHOMO = .True. then
  • if IOP = 1: only para states are included in channel expansion
  • if IOP = -1: only ortho states are included in channel expansion
• NINV: number of inversion doublets included:
  • if NINV = +1, only + inversion levels included
  • if NINV = -1, only - inversion levels included
  • if NINV = 2, both inversion levels included
• KMAX: the maximum projection quantum number included
• JMAX0: the maximum rotational angular momenta or the k = 0 stack
• JMAX1: the maximum rotational angular momenta or the k = 1 stack
• JMAX2: the maximum rotational angular momenta or the k = 2 stack
• JMAX3: the maximum rotational angular momenta or the k = 3 stack
• JMAX4: the maximum rotational angular momenta or the k = 4 stack
• JMAX5: the maximum rotational angular momenta or the k = 5 stack
• JMAX6: the maximum rotational angular momenta or the k = 6 stack
• IPOTSY2: symmetry of potential. if the linear molecule is homonuclear then IPOTSY = 2 and only terms with lambda2 even can be included in the potential, else IPOTSY = 1
• J2MAX: the maximum rotational angular momentum for the linear molecule
• J2MIN: the minimum rotational angular momentum for the linear molecule

The definition of the real system dependent parameters is as follows:

• BROT, CROT: rotational constants of symmetric top
• DROT: rotational constant of diatomic molecule E(jkj2) = BROT j (j + 1) + (CROT - BROT) k² + DROT j₂ (j₂ + 1)